create or replace type my_emp_obj under my_base_obj
(
  emp_no varchar2(3),
  emp_name varchar2(3),
  emp_age number(2),
  constructor function my_emp_obj(my_row_num number,emp_no varchar2,emp_name varchar2,emp_age number) return self as result,
  overriding member function to_string return varchar2
) instantiable final;